L-1 visas are for intra-company transfers. They are issued to foreign employees of a corporation transferring to the U.S. parent or branch of the corporation. The foreign worker must have worked for the corporation for at least one year in the preceding three years prior to getting the visa. An L-1B visa is appropriate for nonimmigrant workers who are being temporarily transferred to the United States based on their specialized knowledge of the company's techniques and methodologies. An L-1A visa is for managers or executives who will either manage people or an essential function of the company.